When a man tells you that he knows the exact truth about anything you are safe in inferring that he is an inexact man.

The great majority of men and women, in ordinary times, pass through life without ever contemplating or criticising, as a whole, either their own conditions or those of the world at large.

The man who pursues happiness wisely will aim at the possession of a number of subsidiary interests in addition to those central ones upon which his life is built.

The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as poetry.

The wise man thinks about his troubles only when there is some purpose in doing so; at other times he thinks about other things, or, if it is night, about nothing at all.

So far I have been speaking of theoretical science, which is an attempt to understand the world. Practical science, which is an attempt to change the world, has been important from the first, and has continually increased in importance, until it has almost ousted theoretical science from men's thoughts.

The wise man will be as happy as circumstances permit, and if he finds the contemplation of the universe painful beyond a point, he will contemplate something else instead.

Cynicism such as one finds very frequently among the most highly educated young men and women of the West, results from the combination of comfort and powerlessness.

Man is the product of causes which had no prevision of the end they were achieving; his origin, his growth, his hopes and fears, his loves and beliefs, are but the outcome of accidental collocations of atoms; no fire, no heroism, no intensity of though and feeling, can preserve an individual life beyond the grave.